[PATCH] FUSE: pass file handle in setattr

This patch passes the file handle supplied in iattr to userspace, in case the
->setattr() was invoked from sys_ftruncate().  This solves the permission
checking (or lack thereof) in ftruncate() for the class of filesystems served
by an unprivileged userspace process.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 29 insertions, 15 deletions

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 83be119ef067..c045cc70c749 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -763,29 +763,29 @@ static int fuse_dir_fsync(struct file *file, struct dentry *de, int datasync)
         return file ? fuse_fsync_common(file, de, datasync, 1) : 0;
 }
 
-static unsigned iattr_to_fattr(struct iattr *iattr, struct fuse_attr *fattr)
+static void iattr_to_fattr(struct iattr *iattr, struct fuse_setattr_in *arg)
 {
         unsigned ivalid = iattr->ia_valid;
-        unsigned fvalid = 0;
-
-        memset(fattr, 0, sizeof(*fattr));
 
         if (ivalid & ATTR_MODE)
-                fvalid |= FATTR_MODE,   fattr->mode = iattr->ia_mode;
+                arg->valid |= FATTR_MODE,   arg->mode = iattr->ia_mode;
         if (ivalid & ATTR_UID)
-                fvalid |= FATTR_UID,    fattr->uid = iattr->ia_uid;
+                arg->valid |= FATTR_UID,    arg->uid = iattr->ia_uid;
         if (ivalid & ATTR_GID)
-                fvalid |= FATTR_GID,    fattr->gid = iattr->ia_gid;
+                arg->valid |= FATTR_GID,    arg->gid = iattr->ia_gid;
         if (ivalid & ATTR_SIZE)
-                fvalid |= FATTR_SIZE,   fattr->size = iattr->ia_size;
+                arg->valid |= FATTR_SIZE,   arg->size = iattr->ia_size;
         /* You can only _set_ these together (they may change by themselves) */
         if ((ivalid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME)) {
-                fvalid |= FATTR_ATIME | FATTR_MTIME;
-                fattr->atime = iattr->ia_atime.tv_sec;
-                fattr->mtime = iattr->ia_mtime.tv_sec;
+                arg->valid |= FATTR_ATIME | FATTR_MTIME;
+                arg->atime = iattr->ia_atime.tv_sec;
+                arg->mtime = iattr->ia_mtime.tv_sec;
+        }
+        if (ivalid & ATTR_FILE) {
+                struct fuse_file *ff = iattr->ia_file->private_data;
+                arg->valid |= FATTR_FH;
+                arg->fh = ff->fh;
         }
-
-        return fvalid;
 }
 
 static int fuse_setattr(struct dentry *entry, struct iattr *attr)
@@ -820,7 +820,7 @@ static int fuse_setattr(struct dentry *entry, struct iattr *attr)
                 return -EINTR;
 
         memset(&inarg, 0, sizeof(inarg));
-        inarg.valid = iattr_to_fattr(attr, &inarg.attr);
+        iattr_to_fattr(attr, &inarg);
         req->in.h.opcode = FUSE_SETATTR;
         req->in.h.nodeid = get_node_id(inode);
         req->inode = inode;
diff --git a/include/linux/fuse.h b/include/linux/fuse.h
index 45c398f08247..b76b558b03d4 100644
--- a/include/linux/fuse.h
+++ b/include/linux/fuse.h
@@ -61,6 +61,7 @@ struct fuse_kstatfs {
 #define FATTR_SIZE      (1 << 3)
 #define FATTR_ATIME     (1 << 4)
 #define FATTR_MTIME     (1 << 5)
+#define FATTR_FH        (1 << 6)
 
 /**
  * Flags returned by the OPEN request
@@ -154,7 +155,20 @@ struct fuse_link_in {
 struct fuse_setattr_in {
         __u32   valid;
         __u32   padding;
-        struct fuse_attr attr;
+        __u64   fh;
+        __u64   size;
+        __u64   unused1;
+        __u64   atime;
+        __u64   mtime;
+        __u64   unused2;
+        __u32   atimensec;
+        __u32   mtimensec;
+        __u32   unused3;
+        __u32   mode;
+        __u32   unused4;
+        __u32   uid;
+        __u32   gid;
+        __u32   unused5;
 };
 
 struct fuse_open_in {